[SPARK-5783] Better eventlog-parsing error messages

core/src/main/scala/org/apache/spark/deploy/history/FsHistoryProvider.scala

@@ -247,6 +247,7 @@ private[history] class FsHistoryProvider(conf: SparkConf) extends ApplicationHis
    */
   private def replay(eventLog: FileStatus, bus: ReplayListenerBus): FsApplicationHistoryInfo = {
     val logPath = eventLog.getPath()
+    logInfo(s"Replaying log path: $logPath")
     val (logInput, sparkVersion) =
       if (isLegacyLogDirectory(eventLog)) {
         openLegacyEventLog(logPath)
@@ -256,7 +257,7 @@ private[history] class FsHistoryProvider(conf: SparkConf) extends ApplicationHis
     try {
       val appListener = new ApplicationEventListener
       bus.addListener(appListener)
-      bus.replay(logInput, sparkVersion)
+      bus.replay(logInput, sparkVersion, logPath.toString)
       new FsApplicationHistoryInfo(
         logPath.getName(),
         appListener.appId.getOrElse(logPath.getName()),

core/src/main/scala/org/apache/spark/deploy/master/Master.scala

@@ -761,7 +761,7 @@ private[spark] class Master(
       val ui = SparkUI.createHistoryUI(new SparkConf, replayBus, new SecurityManager(conf),
         appName + " (completed)", HistoryServer.UI_PATH_PREFIX + s"/${app.id}")
       try {
-        replayBus.replay(logInput, sparkVersion)
+        replayBus.replay(logInput, sparkVersion, eventLogFile)
       } finally {
         logInput.close()
       }

core/src/main/scala/org/apache/spark/scheduler/ReplayListenerBus.scala

@@ -40,21 +40,24 @@ private[spark] class ReplayListenerBus extends SparkListenerBus with Logging {
    *
    * @param logData Stream containing event log data.
    * @param version Spark version that generated the events.
+   * @param sourceName Filename (or other source identifier) from whence @logData is being read
    */
-  def replay(logData: InputStream, version: String) {
+  def replay(logData: InputStream, version: String, sourceName: String) {
     var currentLine: String = null
+    var lineNumber: Int = 1
     try {
       val lines = Source.fromInputStream(logData).getLines()
       lines.foreach { line =>
         currentLine = line
         postToAll(JsonProtocol.sparkEventFromJson(parse(line)))
+        lineNumber += 1
       }
     } catch {
       case ioe: IOException =>
         throw ioe
       case e: Exception =>
-        logError("Exception in parsing Spark event log.", e)
-        logError("Malformed line: %s\n".format(currentLine))
+        logError(s"Exception parsing Spark event log: $sourceName", e)
+        logError(s"Malformed line #$lineNumber: $currentLine\n")
     }
   }
 

core/src/test/scala/org/apache/spark/scheduler/ReplayListenerSuite.scala

@@ -61,7 +61,7 @@ class ReplayListenerSuite extends FunSuite with BeforeAndAfter {
     try {
       val replayer = new ReplayListenerBus()
       replayer.addListener(eventMonster)
-      replayer.replay(logData, SPARK_VERSION)
+      replayer.replay(logData, SPARK_VERSION, logFilePath.toString)
     } finally {
       logData.close()
     }
@@ -120,7 +120,7 @@ class ReplayListenerSuite extends FunSuite with BeforeAndAfter {
     try {
       val replayer = new ReplayListenerBus()
       replayer.addListener(eventMonster)
-      replayer.replay(logData, version)
+      replayer.replay(logData, version, eventLog.getPath().toString)
     } finally {
       logData.close()
     }